
Chapter 1. First-time Users 3
What is a Device?
A device is a programmable logic controller (PLC), a remote terminal unit (RTU), or
some other hardware that monitors, collects, or controls a portion of your
manufacturing process. For example, a device might be a S7-400 PLC.
In order for a driver to communicate with a device, you must enter device information
in your driver configuration. Typically, this information includes the connection you
want to use for the specified communication processor and virtual field device.
What is a Datablock?
A datablock is the specific data you want to access in a device. You can define the
data you want to access by entering the range of memory addresses the device uses to
store the data and the type of data you want to read, (for example, integer, ASCII, or
float). The driver needs the data type to store incoming data correctly for your
human-machine interface (HMI) software.
The driver also needs the following time values:
Poll rate — how frequently to read data.
Access time — how long the driver reads the data from the device and updates the
poll record/datablock when there is no new request from your HMI software.
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